Showing Spotlights 289 - 296 of 500 in category Fabrication Technologies and Devices (newest first):
A hallmark of the Mission: Impossible series shows secret agent Phelps receiving his instructions on a tape that then self-destructs and goes up in a cloud of smoke. Existing self-erasing media are much less dramatic, of course. Most of these materials rely on photochromic molecules. One prominent example is an experimental printing technology with reusable paper developed by Xerox and PARC. While writing with light can be both rapid and accurate, photochromic 'inks' are not necessarily optimal for transforming light-intensity patterns into color variations, because they have relatively low extinction coefficients, are prone to photobleaching, and usually offer only two colors corresponding to the two states of photoisomerizing molecules. Researchers at Northwestern University have now developed a new concept that can be used to produce self-erasing pictures. In contrast to previous techniques, their method allows for multicolored pictures.
Sep 15th, 2009
A few years ago it was discovered that the process of thermal inkjet printing can be applied to fabricate hard tissue scaffolds and, just recently, soft tissue with liquid biomaterials. Research is also underway to use inkjet printing for the fabrication of organic semiconductors, opening a route to the fabrication of high-performance and ultra low-cost electronics such as transparent electronics and thin film solar cells. As a matter of fact, the installation of the world's first silicon-ink based solar cell pilot production was completed this January. In your office, though, you have a choice between inkjet printers and (usually much faster) laser printers. And soon, nanotechnologists might have this choice, too. Researchers in California have demonstrated a novel technique for rapidly 'printing' various nanoparticles such as gold nanoparticles, carbon nanotubes, and semiconducting and metallic nanowires, on a photoconductive surface by light, much like a laser printer prints toner powder on paper.
Sep 8th, 2009
Previously we reported on self-healing nanotechnology anticorrosion coatings, a novel method of multilayer anticorrosion protection including the surface pre-treatment by sonication and deposition of polyelectrolytes and inhibitors. The main novelty of the proposed system was the multi-level protection approach, where the protective systems - the 'smart' multilayers - will not only be a barrier to external impacts, but also respond to changes in their internal structure, and combine in the same system different damage prevention and reparation mechanisms. The team now reports the development of laser-activated nanocontainers filled with corrosion inhibitors. With this new nanomaterial, the healing ability of anticorrosion agents is remotely activated by light.
Aug 27th, 2009
While biofilms are mostly seen from a point of view of pathogenic threats, their complex frameworks with biological behavior, chemical heterogeneity, and physical structure at micro- or even nanoscopic level, biofilms could also be useful in nanofabrication - each of these properties can be an attractive avenue for the development of nanotechnology and material science. Researchers at the Chinese Academy of Sciences have now systematically demonstrated the potential of biofilms for nanostructure engineering. Their research shows that, in principle, biofilms can be an efficient and low-cost approach for large-scale nanotechnology fabrication of various nanostructures.
Aug 24th, 2009
Many of the properties of a given nanoparticle not only depend on its chemical composition but also on its size and shape, i.e. its morphology. These morphological factors have significant impact on a nanoparticle's optical and catalytic properties. Accordingly, nanoparticle manufacturers have developed numerous 'recipes' for synthesizing particles with desired size and shape. To facilitate systematic investigation on the morphology-property relationship, it would be highly desirable if one reaction system can be engineered to yield as many different shapes as possible with minimal degree of parameter tuning. To that end, researchers proposed a way to systematically engineer the morphologies of nanoparticles by constructing an evolutionary tree, which consists of several pathways, each showing a 'string' of evolving shapes over the courses of a single reaction. The tree not only displays the relationship between different shapes, but also offers designing principles for producing more complex shapes by crossing over different pathways during nanoparticle growth.
Jul 29th, 2009
One of the ultimate goals of nanotechnology is to fabricate functional devices at the nanoscale. A nanodevice is expected to integrate components of different material compositions and geometries. The integration is likely to be carried out on silicon if information processing is required. Thus far, the basic building blocks for nanodevices are nanoparticles, for which there are many material candidates; and nanotubes, for which the candidates are fewer (they are mostly carbon, although non-carbon based tubes have been fabricated as well). One-dimensional (1-D) nanomaterials such as nanotubes are useful for component connection and for the transport of charge, heat and vibration. In addition to the limited material selection, common 1-D nanomaterials are usually straight. Composite 1-D nanomaterials are rarer. Often they are also produced as discrete and unorganized units. Scientists in Singapore have now successfully fabricated a family of aligned one-dimensional C-curved nanoarches of different compositions by a simple and scalable method for the first time.
Jul 1st, 2009
One of the outstanding challenges in nanotechnology generally, and in the exploitation of so-called 'bottom-up' assembly of basic nanoscale building blocks such as nanowires, is the development of techniques for assembling large numbers of such nanostructures into more complex systems and precisely specified patterns in an accurate, deterministic manner. For instance, it is possible to build transistors, optical devices, and sensors with very specific properties using nanowires. Thus many useful applications of nanowires will depend on the ability to take these building blocks and organize them in some deterministic way in order to ultimately construct and interface with a nanowire-based system. New work demonstrates the basic capability for, and elucidates some of the guiding principles in, the use of dielectrophoretic behavior to direct the placement of large numbers of nanowires on complex, pre-patterned structures as might be required for integration of nanowires with, for example, silicon-based microelectronic circuitry. It shows that a high level of placement precision can be achieved by paying careful attention to the signal frequency as well as the macroscopic electrode architecture that is employed.
Jun 19th, 2009
The manifold properties of carbon nanotubes (as well as other carbon nanomaterials such as fullerenes and graphene) are related to the various ways the carbon atoms can be arranged to form the tube lattice. Studies have shown that atomic-scale defects in these lattices can strongly influence the electronic and mechanical properties of the nanotubes. The simplest defect type is a vacancy where an atom is missing from the lattice site. Such defects can also be seen as chemically active sites for tube side wall functionalization. Due to the difficulty of observing vacancies directly, it remained unclear under what conditions vacancies in nanotubes are stable or exist at all. Researchers have now demonstrated a technique that allows them to remove carbon atoms from carbon nanotubes with atomic precision and in a controlled way with an extremely focused electron beam.
Jun 18th, 2009